Video games provide an opportunity and challenge for the soft
computational intelligence methods like the symbolic games did for
good old-fashioned artificial intelligence.'' This article reviews
the achievements and future prospects of one particular approach,
that of evolving neural networks, or neuroevolution. This approach
can be used to construct adaptive characters in existing video
games, and it can serve as a foundation for a new genre of games
based on machine learning. Evolution can be guided by human
knowledge, allowing the designer to control the kinds of solutions
that emerge and encouraging behaviors that appear visibly
intelligent to the human player. Such techniques may allow building
video games that are more engaging and entertaining than current
games, and those that can serve as training environments for people.
Techniques developed in these games may also be widely applicable in
other fields, such as robotics, resource optimization, and
intelligent assistants.